1. Field of the Invention
This invention relates to device managing accessing priority to common resources, of functional modules divided over a plurality of local units in each of which they form a local daisy chain.
It applies notably, though not exclusively, to the interconnection of plural trays each containing a limited number of instrumentation modules or boards.
The modules of each tray are interconnected according to the daisy chain principle, thereby enabling management of the priority of the modules in the tray as regards access to the locally available resources.
When the number of modules to be implemented exceeds the capacity of one single tray, plural interconnected trays must then be used.
2. Description of the Prior Art
A first solution consists in interconnecting the daisy chains of all the trays so as to form a single daisy chain.
If the implementation of the daisy chain requires that communications be set up between the modules, this solution has the drawback of mobilizing the communication channels of all the trays.
Another solution consists in using an arbitration device which successively interrogates all the trays, thus activating the daisy chain of each tray to determine the requesting tray. This solution has the drawback of being more time consuming due to the fact that the search for the requesting module with the highest priority requires several interrogations.